Matt Bonner keeps his basketball cards locked away in a trunk inside a storage unit in New Hampshire.

And not just any trunk, but an “airtight, steel trunk,” where unopened packs of basketball cards are neatly organized. Bonner, you see, is a huge collector, and for many years before junior high, the Spurs forward was obsessed with collecting basketball cards.

Of course, the idea of what could be inside each pack of cards was more interesting to Bonner than what actually was inside, which is why to this day the packs remained unopened and safely stored—much to the annoyance of his friends and family.

And like any other child of his era, Bonner, 35, had another love in addition to basketball cards: The original Nintendo.

“I remember my buddy telling me about this mom and pop wholesale store the next town over,“ Bonner recalled to SI.com about his high school collecting days. The store, which Bonner described as Sam’s Club and a flea market having a child, was where he began collecting NES games.

“They had a section of Nintendo games. They were only four dollars. I was like, ‘Oh my goodness!’ I started collecting as many games as I could. I started playing all these games I wished I had as a kid. From that point on I was hooked."

Bonner’s collecting habit didn’t come cheap, even if those Nintendo games only cost four bucks. His high school jobs included two summers at a convenience store, some time at the driving range at the city golf course as well as scorekeeping for Concord Men’s Basketball League.

The passion of collecting has now led Bonner to Gemr, a self-described social community for collectors, where lovers of anything from sneakers to books to NES games can connect, and even trade items. Think of it as a Ebay-Facebook hybrid for your wildest collecting fantasies.

Bonner, a New Hampshire-native who owns nearly 70 NES games, was a natural fit for Gemr, which is based in his home state. It helps that Bonner, a.k.a. the Red Mamba, has his own cult following within NBA circles for his affable goofiness. Who else would you expect to sell you on a social community for collectibles?

These days, the two-time NBA champion isn’t collecting as many basketball cards as he used to. But he loves finding old vinyl records (“I know people always make fun of people who say this, but I really fell in love with the sound”) during free time on the road, and he’s starting to learn more about first-edition books, using the Gemr community as a resource.

Collecting is also a family affair for the Bonner’s. It was his brother Luke who put Matt in touch with Gemr. Luke also collects vinyls himself. (With Matt noting he has to make sure Luke doesn’t try to swipe any from his own collection.)

And although Bonner does not get to play with his NES collection as much as he used to in high school (“it pretty much stopped once I had kids”) he hopes to pass them down to his children and make sure they have “an appreciation for the classics.”

​Most of the players on the Spurs, Bonner said, actually don’t know a ton about his collecting lifestyle, although he hopes his partnership with Gemr starts some more conversations. Such as, which collection would you save if all of them were hanging from a cliff?

“Oh man,” Bonner said, pausing a few beats before answering. “Honestly, it would have to be my basketball and baseball cards. I just remember how hard I had to work to amass that collection. How many lawns I had to mow, how many yards I had to rake. I really had to scrimp and save.”